In measure 1, click on the first note and double click a barre line from the Lines palette.

In measure 2, click on the first note, then shift click a note in the same measure. Then double click a barre line in the Lines palette.

Now observe the "Line Thickness" property in the Inspector for both lines.Expected result: Both lines should be exactly the same.Actual result: The "Reset to style default" button is active in case 2. This corrects itself if you save and reopen the score.